Agtron Scale

Roast Color Classification

The Agtron scale is a widely used reference for classifying the roast color of coffee. Developed by Agtron Corporation, it measures the amount of light reflected by roasted coffee in either whole-bean or ground form.

• Lower values indicate darker coffee because less light is reflected.
• Higher values indicate lighter roasts because more light is reflected.
• The scale described by the source ranges from approximately 25 to 95.

Recording an Agtron value helps keep roast levels consistent when preparing different coffee batches for comparative cupping.

Role in Coffee Cupping

Cupping evaluates a coffee batch under controlled conditions. Consistent roast color, water, lighting, cups, spoons, grinding, and preparation methods make comparisons more reliable and repeatable.

A cupping assessment considers aroma, acidity, body, flavor, aftertaste, sweetness, balance, uniformity, cleanliness of cup, and overall impression. The resulting score provides a shared reference for discussing coffee quality and value.

Common Evaluation Areas

• Aroma: Assessed when the coffee is dry, after hot water is added, and when the crust is broken.
• Acidity: The intensity and quality of the coffee’s lively sensory character.
• Body: The perceived weight and texture of the coffee in the mouth.
• Flavor: Identified using recognized sensory references, such as categories for sweet, cocoa, floral, tea, fruit, and citrus notes.
• Aftertaste: The character, intensity, duration, and pleasantness remaining after tasting.
• Sweetness and balance: The harmony among sweetness, acidity, aroma, body, and flavor.
• Uniformity and clean cup: The consistency of sensory characteristics across the cups representing a batch.

Specialty Coffee Context

The source describes specialty-grade coffee as having no primary defects, no more than three full defects, controlled screen-size variation, and at least one distinctive attribute in taste, acidity, body, or aroma. Physical grading and sensory cupping are used together: grading describes the condition of the beans, while cupping assesses their sensory qualities.

Read the source article on specialty coffee and cupping concepts.